It can be difficult to secure a computing system against unauthorized access when the attacker has physical access to the system. The reason for this difficulty is that physical access to the computing system allows the attacker to probe the electrical traces used to transmit information between components on the motherboard. Since the transmission protocols used to encode the data transmitted across these traces is generally available (because they are usually a standard), an attacker with physical access to the system can watch for sensitive information or even inject data. For example, by finding the decryption key, the attacker can read data via the electrical signals which is otherwise unavailable to software running on that system (because of various software protections). Alternatively, by injecting data at a specific point, a denial of privilege can be converted into a granting of privilege.